Apple recently issued an out-of-warranty battery replacement policy for iPhone 6, 6s, 7, and SE devices in response to reports that they had been intentionally making their hardware obsolete.
If you have one of these devices and want to replace your battery at the newly discounted rate of $29 (down from $79), you have until December 2018. But if you’re in a hurry, you may have to wait to get your new battery. MacRumors reports that wait times at Apple stores and Apple authorized service providers may be as long as 3 months for iPhone 6 Plus devices. Delays of two weeks are expected for iPhone 6 and 6s Plus models, while batteries for 7, 7 Plus, and SE models should be readily available.